netdev_features: convert NETIF_F_LLTX to dev->lltx

JIRA: https://issues.redhat.com/browse/RHEL-59091

commit 00d066a
Author: Alexander Lobakin <aleksander.lobakin@intel.com>
Date:   Thu Aug 29 14:33:37 2024 +0200

    netdev_features: convert NETIF_F_LLTX to dev->lltx

    NETIF_F_LLTX can't be changed via Ethtool and is not a feature,
    rather an attribute, very similar to IFF_NO_QUEUE (and hot).
    Free one netdev_features_t bit and make it a "hot" private flag.

    Signed-off-by: Alexander Lobakin <aleksander.lobakin@intel.com>
    Signed-off-by: Paolo Abeni <pabeni@redhat.com>

Conflicts:
	drivers/net/macsec.c
	drivers/net/veth.c
	net/ipv6/ip6_tunnel.c
	- Context.

	drivers/net/amt.c
	drivers/net/netkit.c
	- Non-existent in RHEL 9.

	drivers/net/ethernet/chelsio/cxgb/cxgb2.c
	drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c
	- Drivers disabled in RHEL 9. Skipped.

	net/dsa/user.c
	- This is slave.c in RHEL 9, but CONFIG_NET_DSA is disabled,
	  so skipped the hunk.

	net/core/net-sysfs.c
	- Code not present because of missing commit 74293ea
	  ("net: sysfs: Do not create sysfs for non BQL device")

Signed-off-by: Michal Schmidt <mschmidt@redhat.com>

Author: michich

Documentation/networking/net_cachelines/net_device.rst

@@ -8,6 +8,7 @@ net_device struct fast path usage breakdown
 Type                                Name                    fastpath_tx_access  fastpath_rx_access  Comments
 ..struct                            ..net_device                                                    
 unsigned_long:32                    priv_flags              read_mostly         -                   __dev_queue_xmit(tx)
+unsigned_long:1                     lltx                    read_mostly         -                   HARD_TX_LOCK,HARD_TX_TRYLOCK,HARD_TX_UNLOCK(tx)
 char                                name[16]                -                   -                   
 struct_netdev_name_node*            name_node                                                       
 struct_dev_ifalias*                 ifalias                                                         

Documentation/networking/netdev-features.rst

@@ -139,14 +139,6 @@ chained skbs (skb->next/prev list).
 Features contained in NETIF_F_SOFT_FEATURES are features of networking
 stack. Driver should not change behaviour based on them.
 
- * LLTX driver (deprecated for hardware drivers)
-
-NETIF_F_LLTX is meant to be used by drivers that don't need locking at all,
-e.g. software tunnels.
-
-This is also used in a few legacy drivers that implement their
-own locking, don't use it for new (hardware) drivers.
-
  * netns-local device
 
 NETIF_F_NETNS_LOCAL is set for devices that are not allowed to move between

Documentation/networking/netdevices.rst

@@ -258,11 +258,11 @@ ndo_get_stats:
 ndo_start_xmit:
 	Synchronization: __netif_tx_lock spinlock.
 
-	When the driver sets NETIF_F_LLTX in dev->features this will be
+	When the driver sets dev->lltx this will be
 	called without holding netif_tx_lock. In this case the driver
 	has to lock by itself when needed.
 	The locking there should also properly protect against
-	set_rx_mode. WARNING: use of NETIF_F_LLTX is deprecated.
+	set_rx_mode. WARNING: use of dev->lltx is deprecated.
 	Don't use it for new drivers.
 
 	Context: Process with BHs disabled or BH (timer),

drivers/net/bareudp.c

@@ -557,7 +557,6 @@ static void bareudp_setup(struct net_device *dev)
 	SET_NETDEV_DEVTYPE(dev, &bareudp_type);
 	dev->features    |= NETIF_F_SG | NETIF_F_HW_CSUM | NETIF_F_FRAGLIST;
 	dev->features    |= NETIF_F_RXCSUM;
-	dev->features    |= NETIF_F_LLTX;
 	dev->features    |= NETIF_F_GSO_SOFTWARE;
 	dev->hw_features |= NETIF_F_SG | NETIF_F_HW_CSUM | NETIF_F_FRAGLIST;
 	dev->hw_features |= NETIF_F_RXCSUM;
@@ -570,6 +569,7 @@ static void bareudp_setup(struct net_device *dev)
 	dev->type = ARPHRD_NONE;
 	netif_keep_dst(dev);
 	dev->priv_flags |= IFF_NO_QUEUE;
+	dev->lltx = true;
 	dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
 }
 

drivers/net/bonding/bond_main.c

@@ -5895,7 +5895,7 @@ void bond_setup(struct net_device *bond_dev)
 #endif /* CONFIG_XFRM_OFFLOAD */
 
 	/* don't acquire bond device's netif_tx_lock when transmitting */
-	bond_dev->features |= NETIF_F_LLTX;
+	bond_dev->lltx = true;
 
 	/* By default, we declare the bond to be fully
 	 * VLAN hardware accelerated capable. Special

drivers/net/dummy.c

@@ -117,9 +117,10 @@ static void dummy_setup(struct net_device *dev)
 	dev->flags |= IFF_NOARP;
 	dev->flags &= ~IFF_MULTICAST;
 	dev->priv_flags |= IFF_LIVE_ADDR_CHANGE | IFF_NO_QUEUE;
+	dev->lltx = true;
 	dev->features	|= NETIF_F_SG | NETIF_F_FRAGLIST;
 	dev->features	|= NETIF_F_GSO_SOFTWARE;
-	dev->features	|= NETIF_F_HW_CSUM | NETIF_F_HIGHDMA | NETIF_F_LLTX;
+	dev->features	|= NETIF_F_HW_CSUM | NETIF_F_HIGHDMA;
 	dev->features	|= NETIF_F_GSO_ENCAP_ALL;
 	dev->hw_features |= dev->features;
 	dev->hw_enc_features |= dev->features;

drivers/net/ethernet/freescale/dpaa/dpaa_eth.c

@@ -250,7 +250,7 @@ static int dpaa_netdev_init(struct net_device *net_dev,
 	net_dev->max_mtu = dpaa_get_max_mtu();
 
 	net_dev->hw_features |= (NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM |
-				 NETIF_F_LLTX | NETIF_F_RXHASH);
+				 NETIF_F_RXHASH);
 
 	net_dev->hw_features |= NETIF_F_SG | NETIF_F_HIGHDMA;
 	/* The kernels enables GSO automatically, if we declare NETIF_F_SG.
@@ -260,6 +260,7 @@ static int dpaa_netdev_init(struct net_device *net_dev,
 	net_dev->features |= NETIF_F_RXCSUM;
 
 	net_dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
+	net_dev->lltx = true;
 	/* we do not want shared skbs on TX */
 	net_dev->priv_flags &= ~IFF_TX_SKB_SHARING;
 

drivers/net/ethernet/mellanox/mlxsw/spectrum.c

@@ -1691,9 +1691,10 @@ static int mlxsw_sp_port_create(struct mlxsw_sp *mlxsw_sp, u16 local_port,
 
 	netif_carrier_off(dev);
 
-	dev->features |= NETIF_F_NETNS_LOCAL | NETIF_F_LLTX | NETIF_F_SG |
+	dev->features |= NETIF_F_NETNS_LOCAL | NETIF_F_SG |
 			 NETIF_F_HW_VLAN_CTAG_FILTER | NETIF_F_HW_TC;
 	dev->hw_features |= NETIF_F_HW_TC | NETIF_F_LOOPBACK;
+	dev->lltx = true;
 
 	dev->min_mtu = 0;
 	dev->max_mtu = ETH_MAX_MTU;

drivers/net/ethernet/netronome/nfp/nfp_net_repr.c

@@ -248,7 +248,6 @@ nfp_repr_fix_features(struct net_device *netdev, netdev_features_t features)
 
 	features = netdev_intersect_features(features, lower_features);
 	features |= old_features & (NETIF_F_SOFT_FEATURES | NETIF_F_HW_TC);
-	features |= NETIF_F_LLTX;
 
 	return features;
 }
@@ -382,7 +381,7 @@ int nfp_repr_init(struct nfp_app *app, struct net_device *netdev,
 	netif_set_tso_max_segs(netdev, NFP_NET_LSO_MAX_SEGS);
 
 	netdev->priv_flags |= IFF_NO_QUEUE | IFF_DISABLE_NETPOLL;
-	netdev->features |= NETIF_F_LLTX;
+	netdev->lltx = true;
 
 	if (nfp_app_has_tc(app)) {
 		netdev->features |= NETIF_F_HW_TC;

drivers/net/ethernet/pasemi/pasemi_mac.c

@@ -1699,8 +1699,9 @@ pasemi_mac_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 
 	netif_napi_add(dev, &mac->napi, pasemi_mac_poll);
 
-	dev->features = NETIF_F_IP_CSUM | NETIF_F_LLTX | NETIF_F_SG |
-			NETIF_F_HIGHDMA | NETIF_F_GSO;
+	dev->features = NETIF_F_IP_CSUM | NETIF_F_SG | NETIF_F_HIGHDMA |
+			NETIF_F_GSO;
+	dev->lltx = true;
 
 	mac->dma_pdev = pci_get_device(PCI_VENDOR_ID_PASEMI, 0xa007, NULL);
 	if (!mac->dma_pdev) {